2 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 RCSID("$OpenBSD: nchan.c,v 1.44 2002/01/21 23:27:10 markus Exp $");
37 * SSH Protocol 1.5 aka New Channel Protocol
38 * Thanks to Martina, Axel and everyone who left Erlangen, leaving me bored.
39 * Written by Markus Friedl in October 1999
41 * Protocol versions 1.3 and 1.5 differ in the handshake protocol used for the
42 * tear down of channels:
44 * 1.3: strict request-ack-protocol:
48 * 1.5: uses variations of:
53 * i.e. both sides have to close the channel
55 * 2.0: the EOF messages are optional
57 * See the debugging output from 'ssh -v' and 'sshd -d' of
58 * ssh-1.2.27 as an example.
62 /* functions manipulating channel states */
64 * EVENTS update channel input/output states execute ACTIONS
67 * ACTIONS: should never update the channel states
69 static void chan_send_ieof1(Channel *);
70 static void chan_send_oclose1(Channel *);
71 static void chan_send_close2(Channel *);
72 static void chan_send_eof2(Channel *);
75 static void chan_shutdown_write(Channel *);
76 static void chan_shutdown_read(Channel *);
78 static char *ostates[] = { "open", "drain", "wait_ieof", "closed" };
79 static char *istates[] = { "open", "drain", "wait_oclose", "closed" };
82 chan_set_istate(Channel *c, u_int next)
84 if (c->istate > CHAN_INPUT_CLOSED || next > CHAN_INPUT_CLOSED)
85 fatal("chan_set_istate: bad state %d -> %d", c->istate, next);
86 debug("channel %d: input %s -> %s", c->self, istates[c->istate],
91 chan_set_ostate(Channel *c, u_int next)
93 if (c->ostate > CHAN_OUTPUT_CLOSED || next > CHAN_OUTPUT_CLOSED)
94 fatal("chan_set_ostate: bad state %d -> %d", c->ostate, next);
95 debug("channel %d: output %s -> %s", c->self, ostates[c->ostate],
101 * SSH1 specific implementation of event functions
105 chan_rcvd_oclose1(Channel *c)
107 debug("channel %d: rcvd oclose", c->self);
109 case CHAN_INPUT_WAIT_OCLOSE:
110 chan_set_istate(c, CHAN_INPUT_CLOSED);
112 case CHAN_INPUT_OPEN:
113 chan_shutdown_read(c);
115 chan_set_istate(c, CHAN_INPUT_CLOSED);
117 case CHAN_INPUT_WAIT_DRAIN:
118 /* both local read_failed and remote write_failed */
120 chan_set_istate(c, CHAN_INPUT_CLOSED);
123 error("channel %d: protocol error: rcvd_oclose for istate %d",
129 chan_read_failed(Channel *c)
131 debug("channel %d: read failed", c->self);
133 case CHAN_INPUT_OPEN:
134 chan_shutdown_read(c);
135 chan_set_istate(c, CHAN_INPUT_WAIT_DRAIN);
138 error("channel %d: chan_read_failed for istate %d",
144 chan_ibuf_empty(Channel *c)
146 debug("channel %d: ibuf empty", c->self);
147 if (buffer_len(&c->input)) {
148 error("channel %d: chan_ibuf_empty for non empty buffer",
153 case CHAN_INPUT_WAIT_DRAIN:
155 if (!(c->flags & CHAN_CLOSE_SENT))
157 chan_set_istate(c, CHAN_INPUT_CLOSED);
160 chan_set_istate(c, CHAN_INPUT_WAIT_OCLOSE);
164 error("channel %d: chan_ibuf_empty for istate %d",
170 chan_rcvd_ieof1(Channel *c)
172 debug("channel %d: rcvd ieof", c->self);
174 case CHAN_OUTPUT_OPEN:
175 chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
177 case CHAN_OUTPUT_WAIT_IEOF:
178 chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
181 error("channel %d: protocol error: rcvd_ieof for ostate %d",
187 chan_write_failed1(Channel *c)
189 debug("channel %d: write failed", c->self);
191 case CHAN_OUTPUT_OPEN:
192 chan_shutdown_write(c);
193 chan_send_oclose1(c);
194 chan_set_ostate(c, CHAN_OUTPUT_WAIT_IEOF);
196 case CHAN_OUTPUT_WAIT_DRAIN:
197 chan_shutdown_write(c);
198 chan_send_oclose1(c);
199 chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
202 error("channel %d: chan_write_failed for ostate %d",
208 chan_obuf_empty(Channel *c)
210 debug("channel %d: obuf empty", c->self);
211 if (buffer_len(&c->output)) {
212 error("channel %d: chan_obuf_empty for non empty buffer",
217 case CHAN_OUTPUT_WAIT_DRAIN:
218 chan_shutdown_write(c);
220 chan_send_oclose1(c);
221 chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
224 error("channel %d: internal error: obuf_empty for ostate %d",
230 chan_send_ieof1(Channel *c)
232 debug("channel %d: send ieof", c->self);
234 case CHAN_INPUT_OPEN:
235 case CHAN_INPUT_WAIT_DRAIN:
236 packet_start(SSH_MSG_CHANNEL_INPUT_EOF);
237 packet_put_int(c->remote_id);
241 error("channel %d: cannot send ieof for istate %d",
247 chan_send_oclose1(Channel *c)
249 debug("channel %d: send oclose", c->self);
251 case CHAN_OUTPUT_OPEN:
252 case CHAN_OUTPUT_WAIT_DRAIN:
253 buffer_clear(&c->output);
254 packet_start(SSH_MSG_CHANNEL_OUTPUT_CLOSE);
255 packet_put_int(c->remote_id);
259 error("channel %d: cannot send oclose for ostate %d",
269 chan_rcvd_close2(Channel *c)
271 debug("channel %d: rcvd close", c->self);
272 if (c->flags & CHAN_CLOSE_RCVD)
273 error("channel %d: protocol error: close rcvd twice", c->self);
274 c->flags |= CHAN_CLOSE_RCVD;
275 if (c->type == SSH_CHANNEL_LARVAL) {
276 /* tear down larval channels immediately */
277 chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
278 chan_set_istate(c, CHAN_INPUT_CLOSED);
282 case CHAN_OUTPUT_OPEN:
284 * wait until a data from the channel is consumed if a CLOSE
287 chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
291 case CHAN_INPUT_OPEN:
292 chan_shutdown_read(c);
293 chan_set_istate(c, CHAN_INPUT_CLOSED);
295 case CHAN_INPUT_WAIT_DRAIN:
297 chan_set_istate(c, CHAN_INPUT_CLOSED);
302 chan_rcvd_eof2(Channel *c)
304 debug("channel %d: rcvd eof", c->self);
305 if (c->ostate == CHAN_OUTPUT_OPEN)
306 chan_set_ostate(c, CHAN_OUTPUT_WAIT_DRAIN);
309 chan_write_failed2(Channel *c)
311 debug("channel %d: write failed", c->self);
313 case CHAN_OUTPUT_OPEN:
314 case CHAN_OUTPUT_WAIT_DRAIN:
315 chan_shutdown_write(c);
316 chan_set_ostate(c, CHAN_OUTPUT_CLOSED);
319 error("channel %d: chan_write_failed for ostate %d",
325 chan_send_eof2(Channel *c)
327 debug("channel %d: send eof", c->self);
329 case CHAN_INPUT_WAIT_DRAIN:
330 packet_start(SSH2_MSG_CHANNEL_EOF);
331 packet_put_int(c->remote_id);
335 error("channel %d: cannot send eof for istate %d",
341 chan_send_close2(Channel *c)
343 debug("channel %d: send close", c->self);
344 if (c->ostate != CHAN_OUTPUT_CLOSED ||
345 c->istate != CHAN_INPUT_CLOSED) {
346 error("channel %d: cannot send close for istate/ostate %d/%d",
347 c->self, c->istate, c->ostate);
348 } else if (c->flags & CHAN_CLOSE_SENT) {
349 error("channel %d: already sent close", c->self);
351 packet_start(SSH2_MSG_CHANNEL_CLOSE);
352 packet_put_int(c->remote_id);
354 c->flags |= CHAN_CLOSE_SENT;
361 chan_rcvd_ieof(Channel *c)
367 if (c->ostate == CHAN_OUTPUT_WAIT_DRAIN &&
368 buffer_len(&c->output) == 0)
372 chan_rcvd_oclose(Channel *c)
377 chan_rcvd_oclose1(c);
380 chan_write_failed(Channel *c)
383 chan_write_failed2(c);
385 chan_write_failed1(c);
389 chan_mark_dead(Channel *c)
391 c->type = SSH_CHANNEL_ZOMBIE;
395 chan_is_dead(Channel *c, int send)
397 if (c->type == SSH_CHANNEL_ZOMBIE) {
398 debug("channel %d: zombie", c->self);
401 if (c->istate != CHAN_INPUT_CLOSED || c->ostate != CHAN_OUTPUT_CLOSED)
404 debug("channel %d: is dead", c->self);
408 * we have to delay the close message if the efd (for stderr) is
411 if (((c->extended_usage != CHAN_EXTENDED_IGNORE) &&
412 buffer_len(&c->extended) > 0)
414 || ((c->extended_usage == CHAN_EXTENDED_READ) &&
418 debug2("channel %d: active efd: %d len %d type %s",
419 c->self, c->efd, buffer_len(&c->extended),
420 c->extended_usage==CHAN_EXTENDED_READ ?
423 if (!(c->flags & CHAN_CLOSE_SENT)) {
427 /* channel would be dead if we sent a close */
428 if (c->flags & CHAN_CLOSE_RCVD) {
429 debug("channel %d: almost dead",
435 if ((c->flags & CHAN_CLOSE_SENT) &&
436 (c->flags & CHAN_CLOSE_RCVD)) {
437 debug("channel %d: is dead", c->self);
446 chan_shutdown_write(Channel *c)
448 buffer_clear(&c->output);
449 if (compat20 && c->type == SSH_CHANNEL_LARVAL)
451 /* shutdown failure is allowed if write failed already */
452 debug("channel %d: close_write", c->self);
454 if (shutdown(c->sock, SHUT_WR) < 0)
455 debug("channel %d: chan_shutdown_write: "
456 "shutdown() failed for fd%d: %.100s",
457 c->self, c->sock, strerror(errno));
459 if (channel_close_fd(&c->wfd) < 0)
460 log("channel %d: chan_shutdown_write: "
461 "close() failed for fd%d: %.100s",
462 c->self, c->wfd, strerror(errno));
466 chan_shutdown_read(Channel *c)
468 if (compat20 && c->type == SSH_CHANNEL_LARVAL)
470 debug("channel %d: close_read", c->self);
473 * shutdown(sock, SHUT_READ) may return ENOTCONN if the
474 * write side has been closed already. (bug on Linux)
475 * HP-UX may return ENOTCONN also.
477 if (shutdown(c->sock, SHUT_RD) < 0
478 && errno != ENOTCONN)
479 error("channel %d: chan_shutdown_read: "
480 "shutdown() failed for fd%d [i%d o%d]: %.100s",
481 c->self, c->sock, c->istate, c->ostate,
484 if (channel_close_fd(&c->rfd) < 0)
485 log("channel %d: chan_shutdown_read: "
486 "close() failed for fd%d: %.100s",
487 c->self, c->rfd, strerror(errno));